JPH0159123B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to tire and wheel rim assemblies, and more particularly to tubeless pneumatic tires and wheel rim assemblies.

In conventional pneumatic tire and wheel rim assemblies, the tire beads are held against their respective bead seats by internal air pressure.

However, when a tire is deflated, the tire beads tend to dislodge from their respective bead seats due to lateral forces and are therefore relatively unsafe. Such an unsafe condition also affects the handling of the vehicle, and if the wheel rim is equipped with a well, the most common type of tire mounting, the tire may be removed from the wheel rim. There is even a danger of leaving completely.

To solve this problem, devices such as beads, spacers, rings, etc. have been proposed. However, the provision of such a device makes the construction of the tire and wheel rim assembly more complex as it must be inserted into position after at least one bead has been seated on the rim. There is a drawback.

A split rim is provided in British Patent No. 890959. The split is adapted to be sealed by gripping therein a tire bead fabric-reinforced, rubber-coated extension. However, with this configuration, the accuracy of gripping the bead extension in the splitter depends on the sealing state of the entire assembly under normal air filling (inflation), so the assembly is difficult. The work becomes complex. By being so gripped, the bead is kept from being moved by deflation or distortion of the tire during normal driving, which also places additional stress on the tire area. become.

It has been found that during cornering, lateral forces are generated at the tread contact patch, displacing the tread laterally relative to the wheel rim. Such forces are transmitted from the tire carcass to the tire bead, where two axial forces occur: a force in the direction of the tire axis and a rotational moment about the circumference through the bead. This rotational force or moment causes the bead heel to rotate around the bead toe, thereby increasing the adhesion between the bead and the rim (if there is insufficient air pressure in the tire, the bead (which is the only force keeping it in place). As a result, the bead slides down on the tapered bead seat to relieve tension on the bead wire and move laterally inward to the rim flange, so that the bead retention force rapidly drives the bead from its normal seated position. The force is smaller than the force exerted by the bead, and the bead leaves its seat and falls into the well.

Various independent static tests have shown that when using a bead breaker tool to remove a tire from a tire rim,
The bead of the tire is not subject to substantially any rotational moment, so that the action on the bead is different from the action of forces that occur during driving. In fact, the removal force applied by the bead breaker tool is almost entirely an axial force; if it is greater than the combined force of the adhesive force between the rim bead seat and the bead and the frictional force due to the bead wire tension, it will cause the bead to move axially. This is an axial force that moves the bead and drops it from the bead seat into the well of the rim.

According to one aspect of the invention, a wheel rim includes a pair of bead seats, one on each side of the wheel rim, and a substantially non-stretchable circumferentially extending bead reinforcement. a tire and a wheel rim assembly comprising a tire and a tire comprising a pair of beads each including a pair of beads, at least one of the beads 11 including the center of the bead reinforcement 12 and radially inward from the bead reinforcement 12; a sector of elastomeric material extending at least 60° around said bead reinforcement 12 from a plane in which it extends axially inwardly of the tire; It is configured to increase the compressive stress in the direction. More preferably, the sector extends at least 90° around the reinforcement,
It does not extend more than 120°.

The sectors could be constructed or made to have a generally constant radius from the axis of the bead wire, and with a hardness that increases with the angle of the sector.

More preferably, the sector is made to have a radius that increases gradually according to its angle. There, as the bead rotates, the thickness of the sector between the reinforcement and bead seat increases, and the sector acts like a cam to create a radial force. Preferably, the material of the sector is a hard material having a hardness of, for example, greater than 60° shore, preferably 70-96° shore, and is provided with any reinforcing material known in the art to provide effective stiffness therefor. It may be reinforced with. Furthermore, increasing radius and increasing hardness may be combined with the angle of the segment or sector.

Sectors may be provided on one or both beads. But at least the outer beads are provided.

In order to eliminate relative slippage between the surface of the bead seat and the surface of the bead in contact with it to ensure rotation, it is preferable to provide means for increasing the friction between these surfaces. This friction increasing means can be, for example, a patterned bead applied to the surface of the tow or a wheel.
It may consist of chemically treated surfaces on the rim surface, grooves knurled or otherwise mechanically formed on the bead seats of the wheel rim, raised teeth in the metal of the wheel rim, and the like. However, in either case, it is a shallow irregularity applied to the bead and/or the rim.

According to another aspect of the invention, a pneumatic tire includes a pair of beads each including a substantially non-stretchable circumferentially extending bead reinforcement, at least one bead being oriented along the axis of the reinforcement. a sector of elastomeric material extending at least 60° around the reinforcement from a radial plane containing the core in an axially inward direction of the bead, the sector generally extending from the axis of the bead reinforcement or bead wire; It is designed to have a constant radius and gradually increasing hardness within the 60° angle range.

According to yet another aspect of the invention, a pneumatic tire includes a pair of beads each including a substantially non-stretchable circumferentially extending bead reinforcement, at least one bead of the reinforcement. a sector of elastomeric material extending at least 60°, preferably 90°, around the reinforcement from a radial plane containing the axis in an axially inward direction of the bead, the sector increasing progressively over the angular range; It seems to have a radius that increases.

The tire is preferably a tubeless tire and is a radial tire, but it can also be a cross-ply tire, a belt bias tire, or a semi-radial tire.

According to yet another aspect of the invention, there is provided a wheel rim configured to increase the frictional grip of a tire bead according to the invention. This wheel rim may include, for example, a shallow circumferential groove or notch knurled into the bead seat area on which the tire bead rotates, or a ridge directed outwardly towards the wheel rim flange. Teeth and other similar irregularities may be added.

The wheel rim has a regular tapered bead seat, a reverse tapered bead seat, or a flat bead seat, and may also include a flat shelf.

The wheel rim may be a split rim or, more preferably, a regular well-based rim. If you are using regular wheels, you can use single wheels and rims. This is economically advantageous because the assembly cost does not increase unlike split wheel rims.

In a deflated tire, according to the invention, the lateral force on the tire tread when the vehicle is steered causes the bead to rotate, thereby increasing the tension in the bead wire, thereby causing the bead to rotate. in place on the wheel rim.

The present invention is particularly useful in designing tires that are safe in deflation conditions, where the tire is preferably radial and has a tread width greater than the wheel rim width between the flanges. The width between the flanges is the distance between the axially outermost points of the flanges of the rim that contact the loaded tire in deflation).
Such tires preferably have an aspect ratio of between 30% and 75%, more preferably between 55% and 70%.

It goes without saying that the present invention can be effectively applied to tires and rims of conventional size and construction.

Embodiments of the invention will now be described in conjunction with the accompanying drawings.

Tires and wheels shown in Figure 1
The tread width of the rim assembly is wider than the rim width.
155/65-310 run-flat tires. The tire carcass is a radial structure having a breaker assembly and a pair of bead wire assemblies 12.

A bead locking structure is constituted by a tire bead 11 including a bead wire 12 and a main carcass reinforcement 13. The bead area of the tire
As the thickness of the material between the wire and the outer bead portion in contact with the surface of the rim bead seat increases, i.e. dimensions A, B and C gradually increase as shown in FIG. It is formed like this. That is, the radius of the material in the 90° sector from X to Y increases progressively from A to C according to the angle within that 90° range.

The single piece wheel rim 16 includes a central well 17 and inner and outer bead seats 18 and 19 to facilitate tire fitting. The tip of each bead seat is a conventional rim flange 20. Bead seats 18 and 19 have shallow knurled grooves,
The tire bead 11 can be effectively gripped by friction.

Because of the construction described above, a lateral force is applied to the tread of the tire where, as the bead area 11 is rotated around the bead wire 12, the increasing thickness of the rubber is applied to the bead. It is pushed between the wire 12 and the bead seat 18. This results in a "cam" action that creates a progressively increasing force in a radial outward direction. The increased force increases the tension in the bead wire, which causes the bead wire 12 and bead seat 1 to tighten around the entire circumference of the tire.
The compression of the material between 8 and 8 increases. This increased compressive force increases the retention force between the bead material and the bead seat 18. That is, the rotation of the bead around its center at any given moment creates the force that holds the bead in its seat. For the bead seat, the bead is the wheel.
It is designed to be able to rotate sufficiently without falling into the well of the rim.
It is made to have ample width.

The material of the bead area, shown dimensions A, B and C, is preferably harder than a typical bead seat to increase the radially outward bead locking force.

In one alternative embodiment, the radius of the sector may be substantially constant throughout, and instead the hardness of the material in the sector increases gradually with the angle of the sector. Even with such a configuration, the bead locking force or bead holding force increases as the bead rotates.

[Brief explanation of drawings]

FIG. 1 shows a tire and a wheel according to the present invention.
A sectional view of the rim assembly, FIG. 2 is a partially detailed view of the bead locking structure in FIG. 1. 11... Tire bead, 12... Bead wire, 13... Carcass, 16... Wheel rim, 17... Well, 18, 19... Bead seat,
20...Rim flange.

Claims (1)

[Scope of Claims] 1. A wheel rim comprising a pair of bead seats, one on each side of the wheel rim, and a substantially non-stretchable circumferentially extending bead reinforcement on each side. and a tire and wheel rim assembly comprising a pair of beads, wherein at least one of the beads 11 has a plane including the center of the bead reinforcement 12 and extending radially inward from the bead reinforcement 12. a sector of elastomeric material extending at least 60° around said bead reinforcement 12 in an axially inward direction of the tire, said sector of elastomeric material extending radially inwards as said bead rotates relative to the bead seat. A tire and wheel rim assembly characterized by being configured to increase compressive stress. 2. In the tire and wheel rim assembly according to claim 1, the sector is provided with the reinforcement 1.
2. A tire and wheel assembly characterized in that the tire and wheel assembly extends at least 90°, but not more than 120°, around 2. 3. A tire and wheel rim assembly according to claim 1 or 2, characterized in that said increasing compressive stress is brought about by progressively increasing the hardness of said elastomeric material; Wheel rim assembly. 4. A tire and wheel rim assembly according to claim 1 or 2, characterized in that the increasing compressive stress is produced by progressively increasing the radius of the elastomeric material.・Rim assembly. 5. Tire and wheel rim assembly according to claim 4, characterized in that the elastomeric material of the sector has a hardness of at least 60° shore, preferably in the range of 70-96° shore; Wheel rim assembly. 6. A tire and wheel rim assembly according to claim 4 or claim 5, characterized in that the hardness of the elastomer material in the sector increases gradually around the sector.・Rim assembly. 7. Tire and wheel rim assembly according to any one of claims 3 to 6, characterized in that the elastomer material of the sector is provided with reinforcing material. . 8. The tire and wheel rim assembly according to any one of claims 1 to 7, including means for increasing friction between the bead seat and the tire bead. Features tire and wheel rim assemblies. 9. The tire and wheel rim assembly of claim 8, wherein the friction increasing means comprises a pattern on the surface of the toe. 10. The tire and wheel rim assembly according to claim 8, characterized in that the friction increasing means comprises a groove formed in the bead seat of the wheel rim by, for example, knurling. tire and wheel rim assemblies. 11. The tire and wheel rim assembly according to any one of claims 1 to 10, characterized in that the tire is a radial tire.